Foam eartips can be generally used with earphones for hearing testing, for stereo earphones, and for cellphone earphones. The slow recovery “yellow foam” E-A-R Classic® Earplugs described in U.S. Pat. Re. 29,487 (1977) has been the basis for hundreds of millions of successful solid foam earplugs used for hearing protection, sold by AEARO Corporation of Indiana. Since 1984, Etymotic Research has supplied ER-3 earphones for hearing testing as described in U.S. Pat. No. 4,763,753 (1988) with foam eartips into which a central hollow tube member has been inserted to allow the sound to be transmitted to the ear canal. This latter construction was also described in U.S. Pat. Re. 29,487. FIG. 1 illustrates an exemplary foam eartip with a central hollow tube inserted therein.
Etymotic Research has also supplied the ER-4 and ER-6 insert earphones (U.S. Pat. Nos. 4,677,679, 4,763,753 and 5,887,070) using similar foam eartips, as well as flanged eartips such as described in U.S. Pat. No. 4,867,149 (1989) and also sold by AEARO as their Ultra-Fit® earplugs. FIG. 2 illustrates an exemplary flanged eartip.
The foam eartip may have approximately 5 dB greater external noise attenuation than the flanged eartip. Additionally, the foam eartip may accommodate a greater range of ears that it can fit, and many users report the foam eartip to be more comfortable than the flanged eartip. However, the foam eartip must be rolled down before being inserted; whereas, a flanged eartip can be simply pushed into the ear canal.
In 1993, AEARO introduced a two-part “mushroom tip” foam earplug under the brand name Push-Ins™ and described in U.S. Pat. No. 5,188,123 (1993). By incorporating a relatively stiff solid plastic center member into the core of a shaped foam earpiece, the Push-Ins™ eartips do not require that the foam be rolled down before inserting it. When slowly pushed into the ear canal, the foam compresses during insertion. Despite the ease of insertion, however, the mushroom tip earplug provides nearly as great attenuation as the classic foam eartip. FIG. 3 illustrates an exemplary two-part mushroom tip foam earplug.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.